Absorbent sheet material



annna'r L, or, or M comma Bos'ron',

vsoannn'r s nner a- ]To Drawing.

1 To dz whom it may concern:

Be it known that I, AIBEBT L. Curr, a citizen of the United States, residing, at Marblehead, in the county of Essex and State of Massachusetts, have invented new anduseful Improvements in Absorbent a Sheet Materials, of which the following is a s ecification.

he object of this invention is to provide a suitable absorbent fibrous material for use in the manufacture of that prepared in which the porous roofing and flooring sheet is impregnated or saturated wlth a waterproof composition, and usually coated with as'phalt'or pitch, and, in some cases,

surfaced with crushed slate or other form of it. In order that the fibrous material to used for such-purposes may be saturated, it must be open and porous, and, in addition, it must possess suflicient tensile strength to prevent itsbeing torn or injured when passed through the saturating tank, the

squeeze rolls and the various other instrumentalities' which operate thereon in the manufacture of the finished roofing or floorelement.

eretofore it has usually been customary to form the felt of a mixture of wool and cotton fibers, although various suggestions have been made for providing a sufliciently porous sheet by the use of leather fiber, Jvaste paper, charcoal and the like, because of the scarcity or high cost of cotton or woolen rags. An attempt to use waste paper news or mixedwith rag fiber, except in very small proportions, has not heretofore been practically successful, because its use in large proportions prevents or destroys the requisite porosity of the felt, eventhough such fillers as charcoal, sawdust or the hke are employed.

I have discovered that a roofing felt of a the desired porosity can be roduced from mnssncnusnr'rs', AssreNon-ro ra n rnm'rxo'rn SACHUSETW, A GOBPOEATION OFMASCHU SETTS.

TERI.

7 Application gflled m 5, 191a Berial No. eraser.

ploy, for example: 250 parts of news and mixed paper; 250 parts of sulphite screenings. i. e; relatively coarse cellulose fiber produce from'chips oft-wood by digestion with calfiium' bisulphite) andf150parts. of kiesel- These are loaded into a beater engine with sufficient water to allow for a proper circulation and are subjected toabeating o eration until the mass is formed-into a p p of the desired densitynorfviscosity. A short time only-say v1 5 to 20 minutes-is required for this operation, aslthe' jpaper fiber, especially news, and sulphite fiber disintegrate readily. Hence-With -'thematerials stated, much less power andtime are required for th'e'beating of the stock than are required when rags, bagging and the like are employed in the mariutacture of the felt. After the pulp has heenprepared, as described, it is formed intoa web or sheet of the desired in the manufacture of roofing; felt. v I Felt thus formed from the .materials stated, has, because of the use of sulphite screenings, the necessary tensile strength to .molten asphaltic or bituminous compounds to penetrate or saturate it. -When kieselguhr, in approximately the proportion stated, ;is employed,'a felt or felt-like material is producedwhich is so porous and absorbent that it may be saturated with the molten compounds more easily and more rapidly than has'heretofore been racticable. Such sheet material, because 0 the large proportion of waste paper used inrits manufacture, and of the small .expenditureuof time and power to beat out the ulp, is most economical to produce, and yet as,in addition, theoptimum qualities of a high de roofing felt. I regard the use of phi screen in connection with paper as. Vd'e-.

sirable, although, so far as I am aware, this thickness by the usual machinery employed material has not been used in the manufacthe fibers is to mat into a dense mass, and a felt formed thereof would be of suchclose texture that it would not absorb the saturating compounds.

I should not regard it as a departure from the invention as set forth in the claims if other fibrous materials were substituted for the waste paper or for the sulphite screenings. For example, though I do not regard it as necessary, one may substitute cotton or other rags for the paper, or for the sulphite screenings, in loading the beater. In fact, one may employ otherwise suitable materials which mat closely together, and which, because of the tendency of the fibers to form a dense and relatively impenetrable mass,'have heretofore been regarded as practically impossible of use for the purpose. In addition to the fact that kieselguhr, because of its structure and capacity, is able to absorb or retain a large amount of the saturating compound, I have discovered that it possesses the decided advantage of interlocking with the fibers of the sheet so that it is retained therein. lit possesses a great advantage over charcoal, sawdust or other organic fillers, since, being fireproof, it removes the fire hazard incident to their storage and use, as it will be remembered that such materials are subject to spontaneous combustion under certain conditions.

Having prepared a fibrous porous absorbent sheet as herein described, it is ready for manufacture into prepared roofing or flooring. The sheet is fed rapidly through a bath of molten asphalt, pitch or resinous or hydrocarbon or other suitable waterproof compound, and, after the excess or surplus compound is removed by squeeze rolls, a iayer,of higher-melting-point pitch or asphalt in a molten or plastic state is applied to one or both faces of the sheet. Grit, if desired, may then be applied to the sheet and partially embedded in the plastic coating thereof, either in plain colors or in designs of different colors. A decided advantage is attained, to wit, that a sheet of felt, as herein described, of a given weight will absorb and retain a greater weight of saturating compound than has heretofore been practicable with commercial roofing felts. Hence the weight of the ultimate product, with a felt of a given weight is greater than has hitherto been regarded as practical, thus effecting a decided saving in the manufacture of the roofing and at the same time improving the quality of the product.

While the especial object of the invention,

as hereinbefore stated, is theproduction of a roofing felt, I have found that porous sheet material produced as herein described is capable of other application in the arts.

For example, I have discovered that, by

grade blotting paper may thus be produced,

by beating to the desired consistency, 240 parts of news paper, 150 parts of sulphite fiber, and 150 parts of kieselguhr. It will be understood, of course, that the resulting pulp may be colored to the desired shade during or after the beating operation. The advantage in thus producing a blotting paper is that less time and expense are consumed than where the aper is made as heretofore from rag stock.

Having thus explained the nature of my said invention and described a way of making and using the same, although without attempting to set forth all of the forms in which it may be made or all of the modes of its use, what I claim is:

9 1. A porous absorbent sheet of roofing felt, consisting of the fibers of news and chemical wood pulp, and an initially porous absorbent fireproof filler, all in intimate admixture. r

2. A porous absorbent roofing felt, consistin of paper fiber and an initially porous absor ent fireproof filler, all in intimate relation in a felted sheet.

sisting of paper fiber and kieselguhr, all in intimate relation in a felted sheet.

in testimony whereof I have atlixed by signature.

ALBERT 1L... CLAPP.

3. A porous absorbent roofing felt, con 

